Combined shoe guide and bull plug for well casings



R. C. BAKER amh 19, 1935.

COMBINED SHOE GUIDE AND BULL PLUG FOR WELL CASINGS Filed Jan. 31, 1923 INVENTOR. fl w 1f @amr Patented Mar. 19, 19 357 g r COMBINED snoE GUIDE AND BULL rLUG FORIWELL CASINGS I Reuben'C. Baker, Coal inga, Calif. Application January 31, 1928, Serial No. 250,831

2 Claims. (Cl. 166-49) This invention relates to deep well drilling tudinally through the shoe, so that the shoe may equipment and particularlypertains to adevice be utilized as a plain guide. This passageway for-use in guiding andfloating a wellxcasing inextends straight through the center of the plug to place in a bore.; 1 r c and due to the fact that the plug is of consider- 5 Prior to my invention guide shoes and floatable length this passageway will create a nozzle 5 ing plugs have been provided'which were adapteffect to enable a forceful stream of water to be ed to be fitted to the lower end of a well casing ejected from the lower end of the plug for the in the casing shoe for guiding and floating the purpose of supporting a washing down action casing into place in the hole. when desired. When desiring to use the device In some instances the guide shoe and floating as a bull plug, the lower end of this passageway 10 plug were combined into one element commonly is plugged by cementing or otherwise securing known as abull plug which had a semi-spherical a tapered plug of cementitious material in the lower end projecting from the end of the shoe lower end thereof. The insertion of this plug and entirely closing the same. As this end was entirely closes the lower end of the casing and semi-spherical it would guide the casing in the enables the latter to be floated into place in the 15 hole and as it entirely closed the end of the hole. casing, the casing could be floated into place; One form which the invention may assume is that is, the resistance'offered by the fluid in the exemplified in the following description and ilwell to displacement by the casing would to a lustrated by way of example in the accompany- 20. certain extent support the casing and relieve ing drawing, in which: 1

the derrick somewhat of its weight. Fig. 1 is a view in central vertical section In other instances the guide shoe was merely through a device embodying the preferred form an open ended sleeve having a rounded or taof my invention, showing the device as it is pered lower end adapted to guide the casing in when used as a plain guide.

the hole. When using such a shoe the fluid Fig. 2 is a similar view of the device when 25 was free to pass upwardly into the casing as the used as a guiding and floating plug. casing was lowered. Fig. 3 is a view of the plug utilized to convert All of these prior devices were formed of the guide into a guiding and floating plug. mental in most instances friable material, such Referring more particularly to the accompanyas cast iron, because it was necessary to drill or ing drawing, 10 indicates a hollow cylindrical 30 break them out after the casing was into place member preferably formed of steel. This memso that the drilling could be proceeded with. her is commonly termed a casing shoe and is in- These devices have not proven entirely satisiacteriorly threaded as at 11 so that it may be contory for the reason that after they were broken nected to the lower end of a string of well casor drilled out, large pieces of metal remained ing. Between the threaded portion 11 and the 35 in the hole which had a very injurious effect on lower end of the shoe its interior surface is formed the drilling tools utilized when continuing the with a plurality of annular locking grooves 12. drilling. Cast within this lower end of the shoe 10 is a The present invention has for its principal obplug 14. This plug is formed entirely of eeject the provision of a guiding and floating dementitious material. At its lower end this plug 40 vice which may be utilized as a casing guide or is formed with a guide portion 15 which projects as a combined guide and float plug which is beyond the end of the shoe and which is of a formed entirely of non-metallic material such diameter substantially the same as the exterior as cement. diameter of the shoe. This guide portion 15 is 4.5 In carrying out the invention into practice, I shown as substantially semi-spherical but it may form a plug in the end of a casing shoe, which be tapered or torpedo-shaped if desired, as any plug is constructed entirely of cementitious maof these shapes will act as guides to guide the terial and is formed with a guide portion at its lower end of the casing into place in the hole. lower end projecting beyond the end of the The plug 14 is formed with a longitudinally 5o shoe. This guide portion is substantially semiextending passageway 16 which extends centrally spherical and of a diameter the same as the eX- through the device. In Fig. 1 this passageway terior diameter of the shoe, so that it will act is shown as unobstructed so that the device may to guide the end of the casing when it is lowered be used as a plain shoe guide for a well casing, in the hole. A passageway of comparatively the guide portion of the plug guiding the casing small diameter is formed centrally and longiinto place and protecting the lower edges of the 55 casing shoe. The fluid in the hole may pass freely through the passageway 16. After the casing has been lowered into place, the plug may be broken or drilled out expeditiously.

In Fig. 2 I have shown the device as shown in Fig. 1 converted into a bull plug, which is in reality a guiding and floating plug. So that this conversion may take place, the lower end. of the passageway 16 is tapered or flared as indicated by the numeral 17., This tapered portion has its larger diameter at the extreme lower end of the plug. Intermediate its ends the tapered portion of the passageway is grooved as at 18.

To plug the passageway, I provide an insert plug 19 which is tapered to correspond with the tapered portion of the lower end o-fthe passageway. This plug is formed with a groove 20 adapted to register with the groove 18 in the passageway when the plug is inserted into place. To secure this insert plug in place, grouting or cement is inserted between it and the sides of the passageway as indicated by the numeral 21 in Fig. 2. After the insert plug 19 has been secured in the lower end of the passageway, the.

device 14 will entirely enclose the lower end of the casing so that it will act as a guiding and,

floating plug, which is commonly termed bull plug.

From the point of production this plug is a very desirable article as all of the plugs may be cast the same. When a plain guide is ordered the plug is soldv without modification and when a bull plug is ordered, the insert plug is cemented into place converting a plain guide into a bull plug. If desired the device may be sold with the insert plug separate so that the user may convert the plug at his option The most important feature of the present invention is the fact that I have provided a plain guide formed entirely of cementitious material,

and also a bull plug formed entirely of cemem titious material. This is a very advantageous feature because it may be expeditiously removed from the lower end of the casing after. it has served its purpose without leaving metallic pieces in the hole, which are very injurious to drilling tools.

While I have shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In combination with a well casing, of a plug of cementitious material formed in the end. 7

thereof, said plug having an uninterrupted passageway formed longitudinally therethrough, the lower end of the passageway having a tapered portion, the larger diameter of the tapered portion being lowermost, and an insert plug fitting said tapered portion and adapted to be cemented therein to close said passageway, said insert plug being held in place solely by the-cement.

2. In combination with a well casing, a casing shoe, a plug of cementitious material cast in the end of the casing shoe, said plug having a guiding portion extending beyond the lower end ofthe casing and of a diameter the same as the exterior diameter of the casing whereby to guide the casing when the same is lowered in a bore, said plug having an uninterrupted passageway formed'longitudinally therethrough, and an insert plug adapted to be inserted in said passageway and cemented therein to close said passageway, said insert plug being held in place solely by thecemen't.

REUBEN c. BAK R. 4o 

